1. Field of the Invention
The present invention is related to a method for soft configuring a memory device, in particular to a method for soft configuring a flash memory card in such a manner that the flash memory card can act as a key card to switch on or off some particular functions of either an application program or the memory device.
2. Description of the Prior Art
Along with the rapid advancement of information technology, demands for information grow explosively. The availability and prevalence of small portable memory devices in recent years, e.g. the flash-memory-based USB flash disk (commonly referred to as “silicon disk drive” or “thumb drive”) and memory cards, e.g. CF (compact flash), MS (memory stick), SD Card (Secure Digital card), MMC (MultiMedia card), and xD, and micro hard disk with CF or USB interface, or the external USB or PCMCIA interfaced 2.5-inch hard disk, have more or less satisfied our increasing longing for “information portability”.
Currently available portable memory devices ordinarily comprise a non-volatile memory array, a controller, and a transfer interface (I/O Interface). The memory array is used for storing data and must be capable of preserving the stored data without external power supply. Thus memory array typically consists of flash memory or a hard disk. The controller comprises circuits, interfaces and driving mechanism for driving and accessing the memory array. The driving mechanism may be provided as a hardware in the form of a command sequencer circuit for executing a series of micro-code programs, or in the form of a micro-controller/micro-processor circuit disposed in the controller of the portable memory device for executing a series of firmware programs. The transfer interface will determine the protocol by which the portable memory device can link and communicate with an external device.
Among memory cards of different specifications, Secure Digital card (called SD card below) and MultiMedia Card (called MMC card below) have the same profile specifications, except that SD card has an additional write protect button, whereas MMC card does not. Otherwise, the only difference between a SD card and a MMC card is the protocol. Currently SD/MMC combo card reader that can support both SD and MMC protocols to access the data in SD card and MMC card is already available on the market. But so far none of flash memory devices (i.e. flash memory cards) on the market are found to support both SD and MMC dual protocols.
U.S. Pat. Nos. 6,676,420 and 6,567,273 disclosed a kind of single flash memory card with two different sets of connectors and transfer interfaces set thereon for supporting double interface. However, both U.S. Pat. No. 6,676,420 and U.S. Pat. No. 6,567,273 need to use two different sets of connectors to transfer data in different interfaces respectively, which are completely different technology from the present invention.
U.S. Pat. Nos. 6,385,677 and 6,658,516 disclosed a kind of single flash memory card with USB transfer interface set thereon in addition to the card's own interface to achieve the function of supporting double interface. However, the memory cards in those patents does not have USB connector, thereby requiring an external adapter for connecting and using USB interface, which apparently resorts to different technology from the present invention.